A collector often is subject to sudden and sometimes passionate attractions toward specific works of art," R. Stanley Johnson, the Chicago dealer-collector, wrote recently. He made the comment in the catalogue for "David to Picasso," an upcoming museum exhibition of drawings collected by him and his wife, Ursula.

"This might result in the casting aside of a certain degree of logic and carefully established principles in order to take immediate advantage of an acquisition opportunity."

How often do collectors cast aside logic and carefully established principles? "It happens very often," Johnson said.

Johnson, like many of his colleagues, is convinced that serious buyers for first-class material are undeterred by the current state of the world.

"The art market," said Marc Blondeau, the dealer who heads Blondeau Fine Art Services in Geneva, "is extremely healthy, not easy but good."

Blondeau’s colleagues in London, New York, Milan, and Paris agree. They were among the dealers, auctioneers, collectors, museum directors, curators, and consultants interviewed by ARTnews correspondents in 22 countries for the 13th annual ARTnews 200 (and its Top Ten), the list of the world’s most active collectors. Sheikh Saud al-Thani of Qatar is new to the list of Top Ten. He is considered to be the art world’s biggest spender. In the last few years he has spent many hundreds of millions of dollars on antiquities, Islamic art, photography, Impessionists, Old Masters, furniture, and jewelry.

Why do collectors cast aside logic? "Sometimes," said Johnson, "it’s because of jealousies among collectors. They will fight for an object at an auction. Then, there’s the collector who finds something that would enhance his collection. He realizes he has a hole in his collection. After he’s paid for it, another hole appears—a month later, a year later, and he says, ’How could I go on living without this?’"